1. Field of the Invention
The present invention relates to an impact energy absorbing structure in an upper portion of a motor vehicle body and, more particularly, to a structure for absorbing an impact energy in an upper portion of a body of a passenger car.
2. Description of the Related Art
U.S. Pat. No. 5,762,392, as for example, proposes an impact energy absorbing structure wherein an energy absorbing interval (space) is formed between an inner panel of a structural member of a vehicle body and an interior member that covers a compartment side of the inner panel and wherein a grating-like energy absorbing body having one or more longitudinal ribs and transverse ribs that are more in number than the longitudinal rib or ribs is disposed within the energy absorbing interval.
In a case where the aforementioned structural member is a roof side rail, the interval space between the roof side rail and a roof lining, that is, an interior member disposed inwardly of the roof side rail, is formed so that the interval distance therebetween gradually decreases from an upper portion of the interval space toward a lower portion thereof (outward in the directions of a vehicle body width), based on a need to ensure easy entrance into the compartment and easy exit therefrom and a need to secure a sufficient clearance between the roof lining and the head of an occupant (head clearance) As a result, the amount of displacement of the energy absorbing body allowed near a lower end of the roof side rail becomes small, so that the amount of energy absorbed by the energy absorbing body becomes less when an impact load occurs near the lower end of the roof side rail than when an equal impact load occurs on an upper portion of the roof side rail. Therefore, in order to ensure that a sufficient amount of energy will be absorbed, it is necessary to increase the interval between the roof side rail and the roof lining. However, this gives rise to problems of a reduction of the ease of entrance and exit and a reduction of the head clearance.
Furthermore, in the case of a front pillar, as for example, the interval distance between the front pillar and a pillar garnish is shorter in a portion near a flange joint portion between an inner panel and an outer panel of the front pillar than in a portion remote from the flange joint portion. Due to circumstances similar to those mentioned above, problems of a reduction of the ease of entrance and exit and a reduction of the visibility arise.